Abstract: Volatile components of essential oil and aqueous extract from Pelargonium graveolens L′Herit. were prepared separately by steam distillation (SD) method and simultaneous distillation-extraction (SDE) method.Their compositions and relative contents were identified by gas chromatography-mass spectrometry (GC-MS) with retention index (RI) and peak area normalization method.Results show that a total of 71 volatile compounds are identified from the geranium essential oil,the main constituents being citronellol,citronellyl formate,geraniol,isomenthone,β-gurjunene,linalool and phenylethyl tiglate.A total of 39 volatile compounds are identified from the geranium aqueous extract,the main constituents being citronellol,linalool,geraniol,isomenthone,α-terpineol,cis-linalool oxide and trans-linalool oxide.The vast majority of volatile components in geranium aqueous extract exists in geranium essential oil,but their content is obviously different.Antioxidation activity of the essential oil and the aqueous extract were evaluated with 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical scavenging methods.The experimental results show that both the geranium essential oil and the geranium aqueous extract display certain DPPH and hydroxyl radical scavenging activities.The DPPH and hydroxyl radical scavenging activity of geranium aqueous extract is higher than that of geranium essential oil.

Key words: geranium essential oil, geranium aqueous extract, volatile components, antioxidation